The recent development of manual guided therapies and the growing consensus regarding heterogeneity among subgroups of adolescents with psychoactive substance use disorders (PSUDs) has resulted in increased interest in clinical research on patient-treatment matching and development of manual guided therapies. The proposed project builds upon our previous studies that have focused on identifying, characterizing, and treating adolescents with PSUD. The long-term objectives of this study are to test hypotheses that suggest that treatment efficacy can be improved significantly by utilizing well characterized treatment methods and by matching patients to distinctive treatment regimen that match their needs. A minimum of 300 adolescents will be recruited from a Partial Hospitalization Program (PHP) for patients with PSUD and enrolled in a 12-week outpatient-aftercare study. Upon completion of the PHP, participants will be randomly assigned into one of three conditions: a minimal treatment maintenance group; a cognitive-behavioral relapse prevention (RP) group; or a modified dynamic (MD) interactional group. The specific aims of this proposal are: 1) To examine whether adolescents who complete PHP for PSUD demonstrate improved maintenance of successful treatment outcome when provided with time-limited continued aftercare in the form of RP or MD outpatient group intervention as compared with those who receive only maintenance aftercare treatment. 2) To test specific patient-treatment matching hypotheses related to these interventions.